Well, one said unlikely and then it happens. I don't fear a true clash of the full hash BTW, because you need to resolve that one in the repository first anyway ;) - But this is only seven hex-digits long. I wonder why. Probably it will be automatically extended if needed?
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hakreJan 18 '13 at 16:22

7 hex digits still gives 268435455 different values, having sha-1 being equally distributed this still gives a quite low risk of conflicts given the amount of to be expected commits over the next years.
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johannesJan 18 '13 at 16:32